Rhematology

Question 1

A 4-year-old boy is brought to the clinic by his parents, who are concerned that he is increasingly “knock-kneed.” His uncle required leg braces as a child, and they worry about long-term gait abnormalities. On examination, the patient’s knees touch when he stands, with a 15° valgus angle at the knee. He walks with a stable gait. What is the most appropriate next step?

A) Refer to orthopedics for therapeutic osteotomy
B) Refer to physical therapy for customized bracing
C) Prescribe quadriceps-strengthening exercises
D) Provide reassurance to the patient and his family

Answer 1

D) Provide reassurance to the patient and his family
🔹 Rationale: This case describes physiologic genu valgum (knock-knees), a normal developmental variant. Toddlers under 2 years typically have genu varum (bowlegs), which transitions to genu valgum and then corrects by age 6. Since this is a self-limiting condition, no intervention is needed, and parents should be reassured. Surgical intervention (A), bracing (B), or exercises (C) are unnecessary.

Question 2

A 2-week-old girl is brought for a routine well-child visit. The physical exam is normal except for a clunking sensation when adducting the hip with posterior pressure applied. What is the most appropriate next step?

A) Referral for orthopedic consultation
B) Reassurance only, with follow-up in 2 weeks
C) Triple diapering and follow-up in 2 weeks
D) Radiograph of the pelvis

Answer 2

A) Referral for orthopedic consultation
🔹 Rationale: The positive Barlow test (hip dislocation on adduction with posterior pressure) suggests developmental dysplasia of the hip (DDH). Early intervention prevents long-term complications. Triple diapering (C) is not recommended, as it can worsen hip positioning. Radiographs (D) are not useful before 4-6 months, as the femoral head is not yet ossified. Observation (B) is not advised since DDH requires prompt treatment.

Question 3

A 7-year-old boy fell on a wet kitchen floor and now has pain and swelling at the third metacarpophalangeal joint. He has limited range of motion due to pain. A radiograph of the hand is shown.

What is the most likely diagnosis?

A) Boxer’s fracture
B) Greenstick fracture
C) Salter-Harris type II fracture
D) Spiral fracture
E) No abnormality

Answer 3

C) Salter-Harris type II fracture
🔹 Rationale: A Salter-Harris type II fracture is the most common pediatric fracture involving the growth plate (physis) and metaphysis. Boxer’s fractures (A) occur in the 5th metacarpal, greenstick fractures (B) are incomplete fractures common in children, spiral fractures (D) occur from twisting forces, and (E) is unlikely due to symptoms.

Question 4

A 7-year-old girl presents with gradual-onset right hip pain and a limp. There is no trauma or systemic symptoms. Examination reveals restricted hip abduction and pain on internal rotation. Her right leg is 2 cm shorter than the left. Radiographs show flattening and sclerosis of the proximal femur with joint space widening.

What is the most likely diagnosis?

A) Iliopsoas bursitis
B) Labral tear
C) Legg-Calvé-Perthes disease
D) Septic arthritis
E) Stress fracture

Answer 4

C) Legg-Calvé-Perthes disease
🔹 Rationale: This condition occurs in children ages 2-12 due to avascular necrosis of the femoral head. It presents with hip pain, a painless limp, and leg-length discrepancy. Radiographs show femoral head sclerosis and flattening.
🔸 Septic arthritis (D) is acute, febrile, and requires urgent drainage. Stress fractures (E) are linked to repetitive use and pain on weight-bearing. Iliopsoas bursitis (A) and labral tears (B) cause mechanical hip symptoms (clicking/snapping).

Question 5

A 5-year-old boy is brought for a preparticipation exam. His mother reports nighttime leg cramping, worse after active days. He has no limp or joint swelling. The physical exam is normal. What is the best next step?

A) Reassurance, with no activity restrictions or treatment
B) Recommending that he avoid running sports
C) Plain films of both hips and knees
D) Serum electrolyte levels
E) Referral to a pediatric orthopedist

Answer 5

A) Reassurance, with no activity restrictions or treatment
🔹 Rationale: The presentation is benign nocturnal limb pain of childhood (“growing pains”), a common condition affecting children ages 4-6 years. The etiology is unknown, and it is self-limiting.
🔸 Serious conditions (e.g., fractures, tumors, metabolic disorders) are unlikely given a normal exam. Imaging (C) and labs (D) are unnecessary, and activity restriction (B) is not needed.

Question 6

A 3-year-old boy presents with right hip pain, fever (37.6°C), and refusal to bear weight. He cries when his leg is moved in any direction. A radiograph of the hip is normal.

What is the most appropriate next step?

A) CBC and erythrocyte sedimentation rate
B) Serum antinuclear antibody level
C) Ultrasonography of the hip
D) MRI of the hip
E) In-office aspiration of the hip

Answer 6

A) CBC and erythrocyte sedimentation rate
🔹 Rationale: The differential includes transient synovitis vs. septic arthritis.
🔸 Septic arthritis red flags:

Fever >38.7°C (101.7°F)
WBC >12,000
ESR >40 mm/hr
Refusal to bear weight

Question 7

A 13-year-old boy presents with a 3-week history of left thigh and knee pain. No trauma or systemic symptoms. Pain worsens with running. On exam, which finding would be pathognomonic for slipped capital femoral epiphysis (SCFE)?

A) Excessive forward passive motion of the tibia with knee flexed
B) Lateral displacement of the patella with active knee flexion
C) Limited internal rotation of the flexed hip
D) Reduced hip abduction with the hip flexed
E) Inability to extend the hip past neutral

Answer 7

C) Limited internal rotation of the flexed hip
🔹 Rationale: SCFE is a displacement of the femoral head through the growth plate, most common in obese adolescent males.
🔸 Key physical exam finding:

Marked limitation of internal hip rotation, worse when hip is flexed to 90°
🔸 Management: Urgent orthopedic consultation and surgical pinning to prevent progression.

Question 8

A 6-year-old boy presents with a purpuric rash on his buttocks and lower extremities, abdominal pain, and bilateral knee arthritis. Laboratory results show normal platelet count, mild proteinuria, and hematuria. Which of the following is the most likely underlying pathophysiology of his condition?

A) IgE-mediated hypersensitivity
B) T-cell mediated destruction of endothelial cells
C) Deposition of IgA immune complexes in small vessels
D) Complement-mediated hemolysis

Answer 8

C) Deposition of IgA immune complexes in small vessels

💡 Rationale:
HSP is an IgA-mediated leukocytoclastic vasculitis affecting small vessels. It presents with palpable purpura, arthritis, and renal involvement (IgA nephropathy). Normal platelet count differentiates it from thrombocytopenic conditions.

Question 9

Which of the following is the most serious long-term complication of Henoch-Schönlein Purpura?

A) Chronic arthritis
B) Recurrent abdominal pain
C) Intussusception
D) Progressive glomerulonephritis

Answer 9

D) Progressive glomerulonephritis

💡 Rationale:
Renal involvement (IgA nephropathy) is the most serious complication and can lead to chronic kidney disease. Intussusception is a known acute complication due to bowel edema but does not have long-term consequences.

Question 10

A 3-year-old boy presents with high fever for 6 days, bilateral conjunctivitis, and a polymorphous rash. He has cracked lips, strawberry tongue, and unilateral cervical lymphadenopathy. His hands are swollen. What is the most concerning complication if left untreated?

A) Myocarditis
B) Rheumatic fever
C) Coronary artery aneurysm
D) Pericardial effusion

Answer 10

C) Coronary artery aneurysm

💡 Rationale:
Kawasaki disease is a medium-vessel vasculitis affecting coronary arteries. If untreated, 25% of cases develop coronary aneurysms leading to myocardial infarction. IVIG reduces this risk significantly.

Question 11

A 2-year-old with Kawasaki disease was treated with IVIG and aspirin. Two weeks later, his fever recurs with worsening rash and arthritis. What is the next best step in management?

A) Repeat IVIG infusion
B) High-dose corticosteroids
C) TNF inhibitors (Infliximab)
D) Methotrexate

Answer 11

A) Repeat IVIG infusion

💡 Rationale:
Refractory Kawasaki disease (persistent or recrudescent fever after initial IVIG) is treated with a second dose of IVIG. If unresponsive, steroids or biologics (e.g., infliximab) are considered.

Question 12

A 4-year-old girl has a painless limp for the past month, primarily in the morning. She has swelling in her left knee but denies fever. Her ANA test is positive, and RF is negative. What is the most likely diagnosis?

A) Oligoarticular JIA
B) Polyarticular JIA
C) Systemic JIA
D) Septic arthritis

Answer 12

A) Oligoarticular JIA

💡 Rationale:
Oligoarticular JIA is the most common subtype, affecting ≤4 joints, usually large joints (knees, ankles). ANA+ increases the risk of chronic uveitis, necessitating regular ophthalmologic screening.

Question 13

A 12-year-old boy has chronic arthritis affecting 8 joints, including the small joints of the hands. He has mild fever and is found to be RF-positive. What is the best initial treatment?

A) NSAIDs
B) Methotrexate
C) High-dose steroids
D) TNF inhibitors

Answer 13

B) Methotrexate

💡 Rationale:
Polyarticular JIA (≥5 joints, RF+) has a higher risk of joint damage and resembles adult RA. Methotrexate is first-line in moderate-severe cases. Biologics (TNF inhibitors) are used for refractory disease.

Question 14

A 16-year-old girl presents with malar rash, fatigue, photosensitivity, and oral ulcers. Lab results show positive ANA, low complement levels, and anti-dsDNA antibodies. Which of the following is the most serious complication in pediatric lupus?

A) Cerebritis
B) Lupus nephritis
C) Pericarditis
D) Autoimmune hemolytic anemia

Answer 14

B) Lupus nephritis

💡 Rationale:
Lupus nephritis is the leading cause of morbidity and mortality in pediatric SLE. It requires renal biopsy and aggressive immunosuppression (steroids + mycophenolate or cyclophosphamide).

Question 15

Which of the following markers is most specific for diagnosing Systemic Lupus Erythematosus?

A) ANA
B) Anti-dsDNA
C) Rheumatoid factor
D) ESR

Answer 15

B) Anti-dsDNA

💡 Rationale:
ANA is sensitive but not specific. Anti-dsDNA and Anti-Smith are highly specific for SLE. Low C3/C4 suggests active disease.

Question 16

A 10-year-old girl presents with chronic arthritis affecting multiple joints, daily spiking fevers, and a salmon-colored evanescent rash. Labs show elevated ESR, CRP, leukocytosis, and thrombocytosis. What is the most likely diagnosis?

A) Polyarticular JIA
B) Systemic Juvenile Idiopathic Arthritis (sJIA)
C) Acute Rheumatic Fever
D) Psoriatic Arthritis

Answer 16

B) Systemic Juvenile Idiopathic Arthritis (sJIA)

💡 Rationale:
Systemic JIA (Still’s disease) is the only subtype of JIA associated with daily fevers, transient maculopapular rash, and hepatosplenomegaly. Labs show marked inflammation (↑ WBC, CRP, ESR, thrombocytosis).

Question 17

Which of the following skin findings is characteristic of Juvenile Idiopathic Arthritis?

A) Gottron papules
B) Salmon-pink rash with fever spikes
C) Erythema migrans
D) Periorbital heliotrope rash

Answer 17

B) Salmon-pink rash with fever spikes

💡 Rationale:
Systemic JIA is associated with an evanescent, maculopapular rash that appears during fever spikes and resolves without residual pigmentation. Gottron papules & heliotrope rash are seen in juvenile dermatomyositis, while erythema migrans suggests Lyme disease.

Question 18

A 7-year-old boy presents with a limp and hip pain for 2 months. X-ray shows flattening and sclerosis of the femoral head. What is the most likely diagnosis?

A) Developmental Dysplasia of the Hip (DDH)
B) Transient Synovitis
C) Legg-Calvé-Perthes Disease
D) Slipped Capital Femoral Epiphysis (SCFE)

Answer 18

C) Legg-Calvé-Perthes Disease

💡 Rationale:
Legg-Calvé-Perthes disease is avascular necrosis of the femoral head, common in boys aged 4-10. It presents with insidious hip pain, limp, and limited internal rotation & abduction. X-ray shows sclerosis, fragmentation, and flattening of the femoral head.

Question 19

A 12-year-old obese boy presents with hip pain and limp for 2 weeks. He has external rotation of the affected leg when attempting hip flexion. X-ray shows posterior-inferior displacement of the femoral head. What is the next best step?

A) Non-weight bearing and urgent orthopedic referral
B) NSAIDs and observe
C) Physical therapy
D) Hip spica casting

Answer 19

A) Non-weight bearing and urgent orthopedic referral

💡 Rationale:
Slipped Capital Femoral Epiphysis (SCFE) occurs in obese adolescents, causing displacement of the femoral head. It requires immediate surgical pinning to prevent avascular necrosis.

Question 20

A 5-year-old boy presents with a stiff neck, fever, and difficulty turning his head. Examination shows torticollis with tenderness over the C1-C2 region. Lateral neck X-ray shows increased retropharyngeal space. What is the most likely diagnosis?

A) Atlantoaxial instability
B) Cervical disc herniation
C) Retropharyngeal abscess
D) Klippel-Feil Syndrome

Answer 20

C) Retropharyngeal abscess

💡 Rationale:
Retropharyngeal abscess is a common cause of acquired torticollis, often following upper respiratory infections. Fever, neck stiffness, and dysphagia are key features. X-ray shows widened prevertebral space, and CT confirms diagnosis.

Question 21

A child with Down syndrome is undergoing a preoperative assessment for tonsillectomy. Which cervical spine abnormality should be ruled out?

A) Atlantoaxial instability
B) Cervical radiculopathy
C) Klippel-Feil Syndrome
D) Congenital scoliosis

Answer 21

A) Atlantoaxial instability

💡 Rationale:
Atlantoaxial instability is common in Down syndrome due to ligamentous laxity at C1-C2. Preoperative lateral cervical spine X-rays are needed to assess for subluxation, which may cause spinal cord compression during intubation.

Question 22

A newborn girl is found to have a positive Ortolani and Barlow test. She was delivered breech. What is the best initial imaging study?

A) Hip X-ray
B) Hip ultrasound
C) CT scan
D) MRI

Answer 22

B) Hip ultrasound

💡 Rationale:
Hip ultrasound is the gold standard for diagnosing DDH in infants <6 months. X-rays are only useful after ossification of the femoral head (>6 months old).

Question 23

A 2-year-old presents with limb-length discrepancy and an asymmetric gluteal fold. What is the best next step?

A) Observation
B) Pavlik harness
C) Closed reduction with hip spica cast
D) Surgical open reduction

Answer 23

C) Closed reduction with hip spica cast

💡 Rationale:
After 6 months, DDH cannot be treated with a Pavlik harness. Closed reduction followed by a hip spica cast is the treatment of choice for children 6-24 months. Open reduction is needed for older children.

Question 24

A 3-year-old boy presents with acute onset of fever (39.5°C), refusal to bear weight on his right leg, and a swollen, warm knee joint. Laboratory tests show WBC 17,000/mm³, ESR 65 mm/hr, CRP 7 mg/dL. Which of the following is the most appropriate next step?

A) MRI of the knee
B) Joint aspiration and culture
C) X-ray of the knee
D) Start empiric antibiotics and observe

Answer 24

B) Joint aspiration and culture

💡 Rationale:

Septic arthritis is a medical emergency requiring immediate joint aspiration for cell count, Gram stain, and culture.
WBC >50,000/mm³ in synovial fluid with >90% PMNs confirms septic arthritis.
Delayed treatment can lead to joint destruction.

Question 25

Which of the following is the most common causative organism of septic arthritis in a 2-year-old child? A) Staphylococcus aureus B) Neisseria gonorrhoeae C) Kingella kingae D) Streptococcus pyogenes

Answer 25

A) Staphylococcus aureus 💡 Rationale: S. aureus is the most common cause of septic arthritis in all age groups. Kingella kingae is common in children <4 years but less frequent than S. aureus. N. gonorrhoeae is a leading cause in sexually active adolescents.

Question 26

A 4-year-old boy presents with a limp, mild hip pain, and low-grade fever for 2 days. He recently had a viral upper respiratory infection. On examination, his hip movements are mildly painful, but there is no erythema or swelling. Laboratory studies show normal WBC, ESR 20 mm/hr, CRP 0.8 mg/dL. What is the most likely diagnosis? A) Septic arthritis B) Osteomyelitis C) Transient synovitis D) Legg-Calvé-Perthes disease

Answer 26

C) Transient synovitis 💡 Rationale: Post-viral inflammatory reaction in the synovium → most common cause of acute hip pain in children. Low/no fever, normal/mildly elevated inflammatory markers, and pain improves with NSAIDs.

Question 27

Which of the following findings most strongly suggests transient synovitis over septic arthritis? A) Severe pain with passive motion B) Fever >39°C C) WBC >15,000/mm³ and ESR >40 mm/hr D) Rapid improvement of symptoms with NSAIDs

Answer 27

D) Rapid improvement of symptoms with NSAIDs 💡 Rationale: Septic arthritis does NOT improve with NSAIDs and requires urgent drainage. Transient synovitis is self-limited, resolves in 1-2 weeks, and is not associated with high fever or leukocytosis.

Question 28

A 7-year-old boy presents with progressive painless limp and mild knee pain for 3 months. He denies trauma or recent illness. On exam, he has limited hip abduction and internal rotation. X-ray of the hip shows flattening and sclerosis of the femoral head. What is the best next step? A) Observation B) Hip spica casting C) Surgical osteotomy D) NSAIDs and physical therapy

Answer 28

A) Observation 💡 Rationale: Legg-Calvé-Perthes Disease is idiopathic avascular necrosis of the femoral head, common in boys aged 4-10 years. Self-resolves in younger children (<6 years old) with mild symptoms. Bracing or surgery for older children (>6 years) or severe cases.

Question 29

Which of the following is the earliest imaging finding in Legg-Calvé-Perthes disease? A) Femoral head fragmentation on X-ray B) Joint space widening on X-ray C) Crescent sign on X-ray D) Bone marrow edema on MRI

Answer 29

D) Bone marrow edema on MRI 💡 Rationale: MRI detects early bone marrow edema before X-ray changes. X-ray findings (widening of joint space, sclerosis, and flattening) appear later.

Question 30

A 14-year-old obese boy presents with progressive left hip and knee pain for 2 months. He walks with an antalgic gait and has external rotation of the hip with decreased internal rotation. X-ray (frog-leg lateral view) shows posterior-inferior displacement of the femoral head. What is the best next step? A) Non-weight bearing and urgent surgical fixation B) NSAIDs and weight loss counseling C) Serial hip X-rays for monitoring D) Hip spica cast

Answer 30

A) Non-weight bearing and urgent surgical fixation 💡 Rationale: SCFE is an orthopedic emergency → immediate non-weight bearing and surgical pinning to prevent further slippage. X-ray shows "ice cream slipping off cone" sign.

Question 31

Which of the following is a risk factor for developing SCFE? A) Prematurity B) Growth hormone deficiency C) Obesity D) Viral infections

Answer 31

C) Obesity 💡 Rationale: Obesity is the strongest risk factor for SCFE due to increased mechanical stress on the growth plate. Other risk factors: Growth hormone disorders (e.g., hypothyroidism, GH deficiency).

Question 32

A 6-year-old boy presents with fever, refusal to bear weight, and localized tenderness over the right tibia. Labs show WBC 14,000/mm³, CRP 8 mg/dL, ESR 75 mm/hr. MRI confirms a bone abscess. What is the most likely causative organism? A) Staphylococcus aureus B) Streptococcus pyogenes C) Kingella kingae D) Pseudomonas aeruginosa

Answer 32

A) Staphylococcus aureus 💡 Rationale: S. aureus is the most common cause of osteomyelitis in all age groups. Kingella kingae is common in children <4 years. Pseudomonas is common in puncture wounds.

Question 33

Which imaging modality is most sensitive for early detection of osteomyelitis? A) X-ray B) CT scan C) MRI D) Bone scan

Answer 33

C) MRI 💡 Rationale: MRI is the gold standard for early osteomyelitis detection before X-ray changes appear. X-ray findings (periosteal elevation, lytic lesions) appear late (10-14 days).

Question 34

A 6-year-old child with Down syndrome is undergoing a preoperative evaluation for an elective tonsillectomy. The pediatrician orders cervical spine X-rays in flexion and extension. What is the primary reason for this evaluation? A) Rule out congenital scoliosis B) Assess for cervical radiculopathy C) Detect atlantoaxial instability (AAI) D) Identify early signs of juvenile arthritis

Answer 34

C) Detect atlantoaxial instability (AAI) 💡 Rationale: AAI occurs in 10-30% of children with Down syndrome due to ligamentous laxity at C1-C2. Screening cervical spine X-rays (flexion/extension views) are recommended before procedures requiring neck manipulation (e.g., intubation). Sudden hyperextension during intubation may cause spinal cord compression.

Question 35

A 7-year-old girl with Down syndrome presents with progressive difficulty walking, clumsiness, and neck pain. Neurological exam reveals hyperreflexia, positive Babinski sign, and spasticity in the lower limbs. What is the most likely diagnosis? A) Cerebral palsy B) Atlantoaxial instability C) Guillain-Barré syndrome D) Myelomeningocele

Answer 35

B) Atlantoaxial instability 💡 Rationale: Cervical myelopathy (spinal cord compression) is a late complication of AAI and presents with upper motor neuron signs (hyperreflexia, spasticity, Babinski sign). Surgical stabilization (posterior cervical fusion) is required if myelopathy is present.

Question 36

A 9-year-old boy with juvenile idiopathic arthritis (JIA) presents with progressive torticollis, restricted neck movement, and pain on neck flexion. Which of the following is the most appropriate initial imaging study? A) Cervical spine X-ray (AP, lateral, flexion-extension views) B) MRI of the cervical spine C) CT scan of the cervical spine D) Bone scan

Answer 36

A) Cervical spine X-ray (AP, lateral, flexion-extension views) 💡 Rationale: Children with JIA have an increased risk of cervical spine involvement, leading to AAI. Initial imaging should include lateral and flexion-extension X-rays to assess C1-C2 stability. MRI is used if neurological symptoms are present.

Question 37

A newborn girl is noted to have a positive Ortolani test during a routine neonatal exam. She was born breech at 39 weeks. What is the most appropriate next step? A) Observation and re-evaluation at 2 months B) Immediate hip ultrasound C) Hip X-ray D) MRI of the hip

Answer 37

B) Immediate hip ultrasound 💡 Rationale: Hip ultrasound is the best initial imaging study for DDH in infants <6 months. X-rays are only useful >6 months, when ossification of the femoral head occurs. Breech delivery is a major risk factor for DDH.

Question 38

A 4-month-old infant is diagnosed with developmental dysplasia of the hip (DDH). What is the first-line treatment? A) Pavlik harness B) Hip spica cast C) Closed reduction with traction D) Open surgical reduction

Answer 38

A) Pavlik harness 💡 Rationale: Pavlik harness is the first-line treatment for DDH in infants <6 months and holds the hip in flexion and abduction. Hip spica casting is used if Pavlik harness fails or in older infants.

Question 39

1. A 15-month-old child presents with bilateral bowing of the legs. The child has no history of pain, no significant medical history, and has started walking recently. Physical examination reveals symmetric bowing without tenderness or deformities in the upper limbs. What is the most appropriate next step? A) Obtain serum calcium, phosphate, and alkaline phosphatase levels B) Obtain standing X-rays of the lower extremities C) Reassure the parents and schedule a follow-up at 2 years D) Refer to pediatric orthopedic surgery

Answer 39

C) Reassure the parents and schedule a follow-up at 2 years 📝 Rationale: Physiologic Genu Varum is normal up to 2 years of age and resolves by 3 years. Nelson’s Pediatrics emphasizes observation unless the bowing is severe, asymmetric, progressive, or associated with other skeletal abnormalities. Investigations (labs, imaging) are only needed if bowing persists beyond 2-3 years or if there are signs of an underlying disorder (e.g., rickets, Blount’s disease).

Question 40

2. A 5-year-old boy presents with persistent bowing of the legs that appears asymmetric. Physical examination reveals significant varus angulation, especially on the left side, with an altered gait pattern. X-ray findings show medial beaking of the proximal tibia and an abnormal metaphyseal-diaphyseal angle. What is the most likely diagnosis? A) Physiologic genu varum B) Rickets C) Blount’s disease D) Skeletal dysplasia

Answer 40

C) Blount’s disease 📝 Rationale: Blount’s disease (tibia vara) is a progressive, pathologic condition caused by abnormal medial growth plate compression, leading to asymmetric bowing. Nelson’s states that it is more common in obese children and early walkers. X-ray findings: Medial beaking and metaphyseal-diaphyseal angle > 11° are pathognomonic. Treatment: Bracing if mild (in children <3 years); surgery for severe/progressive cases.

Question 41

3. A 7-year-old girl with a history of joint hypermobility is evaluated for knee instability. She complains of difficulty standing for long periods and hyperextension of her knees when walking. Physical examination shows excessive knee extension beyond the normal range but no pain. Which of the following conditions is most likely? A) Genu recurvatum due to Marfan syndrome B) Quadriceps tendon rupture C) Osgood-Schlatter disease D) Transient synovitis of the knee

Answer 41

A) Genu recurvatum due to Marfan syndrome 📝 Rationale: Nelson’s Pediatrics highlights that genu recurvatum (knee hyperextension) is associated with Ehlers-Danlos and Marfan syndrome, both of which involve connective tissue abnormalities leading to joint hypermobility. Key clinical features: Excessive knee extension, no pain, and a history of hypermobility. Management: Physical therapy for strengthening; bracing in severe cases.

Question 42

4. A 10-year-old boy with a history of polyarticular juvenile idiopathic arthritis (JIA) presents with difficulty fully extending his knee. Physical exam shows limited range of motion and a flexed knee posture at rest. Which of the following is the best initial management? A) Serial casting B) Physical therapy and splinting C) Immediate surgical intervention D) NSAIDs alone

Answer 42

B) Physical therapy and splinting 📝 Rationale: Nelson’s states that flexion contractures of the knee are common in JIA, especially if untreated or poorly managed. First-line treatment includes physical therapy and splinting to prevent worsening contractures. Surgery (soft tissue release) is only for severe cases that do not respond to conservative management.

Question 43

1. A 3-year-old child presents with in-toeing gait noted by parents. On examination, the patella faces forward, but the foot points inward. There is no history of pain, tripping, or weakness. The parents are concerned and want to know the best course of action. What is the most appropriate next step? A) Order tibial X-rays to assess bone structure B) Reassure parents and schedule follow-up at 5 years C) Recommend bracing to correct the condition D) Refer for surgical correction

Answer 43

B) Reassure parents and schedule follow-up at 5 years 📝 Rationale: Nelson’s Pediatrics highlights Internal Tibial Torsion as the most common cause of in-toeing in children <5 years. The patella facing forward with inward-pointing feet differentiates it from femoral anteversion (where both patella and feet turn inward). Observation is key as most cases resolve by 5-8 years. X-rays and surgery are NOT needed unless the deformity persists beyond 8 years or is severe.

Question 44

2. A 9-year-old boy presents with persistent in-toeing that has not improved since early childhood. His tibial rotation measurements confirm excessive internal tibial torsion. He experiences frequent tripping and difficulty running. What is the most appropriate management? A) Observation and reassurance B) Serial casting to realign the tibia C) Derotational osteotomy D) Physical therapy and bracing

Answer 44

C) Derotational osteotomy 📝 Rationale: Nelson’s states that internal tibial torsion should resolve by 5-8 years. If persistent beyond 8 years and causing functional impairment (tripping, difficulty running), surgical correction via osteotomy is indicated. Bracing and casting have no proven benefit in correcting this condition in older children.

Question 45

3. A 7-year-old child is evaluated for out-toeing of the right leg. His parents note that he has trouble running and appears clumsy. On examination, the patella and foot both face outward, and the thigh-foot angle is increased beyond the normal range. What is the most likely diagnosis? A) Internal tibial torsion B) External tibial torsion C) Femoral anteversion D) Metatarsus adductus

Answer 45

B) External tibial torsion 📝 Rationale: Nelson’s highlights external tibial torsion as a common cause of out-toeing, usually unilateral, and associated with patellar instability. The patella and foot facing outward confirm external tibial torsion. Femoral anteversion would cause the patella and foot to face inward ("W-sitting" pattern). Management: Observation in mild cases, surgical correction (osteotomy) if persistent and symptomatic.

Question 46

4. A 10-year-old boy with a history of unilateral out-toeing presents with complaints of knee pain and difficulty in sports. Examination reveals increased thigh-foot angle on the affected side and lateral patellar tracking. What is the best management option? A) Reassurance and observation B) Serial casting and physical therapy C) Derotational osteotomy D) Custom orthotics for gait correction

Answer 46

C) Derotational osteotomy 📝 Rationale: Nelson’s emphasizes that external tibial torsion may cause patellar instability and functional limitations. Surgery is indicated if symptomatic and persistent beyond 10 years. Physical therapy and orthotics do not correct rotational bone deformities.

Question 47

1. A newborn is diagnosed with congenital clubfoot. Which of the following best describes the primary components of this deformity? A) Flatfoot, hindfoot eversion, ankle equinus, and tibial rotation B) Cavus, forefoot adduction, hindfoot varus, and equinus C) Metatarsus adductus, pes planus, ankle valgus, and dorsiflexion contracture D) Hallux valgus, hindfoot pronation, ankle equinus, and plantarflexion contracture

Answer 47

B) Cavus, forefoot adduction, hindfoot varus, and equinus 📝 Rationale: Nelson’s defines the classic "CAVE" deformity of congenital clubfoot: Cavus (high arch) Adduction of the forefoot Varus of the hindfoot Equinus (ankle plantarflexion) Treatment: Ponseti method (serial casting, Achilles tenotomy, bracing).

Question 48

2. A 3-week-old infant is diagnosed with congenital clubfoot. The pediatrician counsels the parents on the best treatment approach. Which of the following is the gold standard for initial management? A) Early Achilles tendon release B) Serial casting followed by Achilles tenotomy and bracing C) Immediate surgical correction within the first 3 months D) Physical therapy and foot orthotics

Answer 48

B) Serial casting followed by Achilles tenotomy and bracing 📝 Rationale: Nelson’s emphasizes that the Ponseti method is the gold standard for clubfoot management. Steps: Serial casting (initiated within weeks of birth) Percutaneous Achilles tenotomy if necessary Bracing (Dennis-Brown splint) to prevent recurrence Surgical correction is reserved for severe or refractory cases.

Question 49

3. A 2-year-old boy presents with in-toeing and a curved lateral border of the foot. His parents are concerned about his walking pattern. Passive manipulation of the foot allows for correction to a neutral position. What is the most appropriate next step in management? A) Reassure parents and observe B) Refer to orthopedics for surgical correction C) Apply serial casting immediately D) Order X-rays to evaluate skeletal alignment

Answer 49

A) Reassure parents and observe 📝 Rationale: Nelson’s highlights that metatarsus adductus is the most common cause of in-toeing in infants. Flexible metatarsus adductus (corrects with passive manipulation) resolves spontaneously by 12-24 months. Bracing or casting is only required for rigid deformities.

Question 50

4. A 9-year-old boy presents with foot pain after prolonged activity. On examination, he has a flattened medial arch that reappears when he stands on his toes. His foot is flexible without any rigidity. What is the most appropriate next step? A) Custom orthotics and stretching exercises B) Serial casting to correct the deformity C) Surgical correction to stabilize the arch D) Reassurance that the condition is normal

Answer 50

D) Reassurance that the condition is normal 📝 Rationale: Flexible pes planus (flatfoot) is normal in children and usually resolves by adolescence. Nelson’s stresses that no treatment is needed for asymptomatic cases. Orthotics or stretching are only indicated if the child has pain.

Question 51

5. A 14-year-old girl presents with chronic foot pain and difficulty walking. She has had rigid flatfoot since childhood. Examination reveals a stiff, painful foot with restricted subtalar motion. X-rays show bony bridging between the talus and calcaneus. What is the most likely diagnosis? A) Flexible pes planus B) Metatarsus adductus C) Tarsal coalition D) Pes cavus

Answer 51

C) Tarsal coalition 📝 Rationale: Tarsal coalition is an abnormal bony or cartilaginous connection between tarsal bones, leading to rigid pes planus. Nelson’s identifies limited subtalar motion and foot pain as key signs. X-rays may show bridging (especially talocalcaneal or calcaneonavicular coalitions). Management: Conservative (NSAIDs, orthotics), but surgery for persistent pain.

Question 52

6. A 12-year-old girl is evaluated for persistent ankle instability and difficulty walking. She has a high-arched foot with clawed toes and difficulty dorsiflexing. Family history is significant for progressive gait problems in her father. What is the most likely underlying condition? A) Tarsal coalition B) Charcot-Marie-Tooth disease C) Idiopathic pes planus D) Metatarsus adductus

Answer 52

B) Charcot-Marie-Tooth disease 📝 Rationale: Pes cavus (high-arched foot) should raise suspicion for neuromuscular disorders, especially Charcot-Marie-Tooth disease. Nelson’s highlights: Progressive foot drop Clawed toes Family history of neuropathy Management: Bracing (ankle-foot orthosis), physical therapy, surgical correction in severe cases.

Question 53

1. A 3-year-old obese boy presents with persistent bilateral bowing of the legs that has worsened over the past year. Examination reveals significant tibial varus, asymmetric leg lengths, and a waddling gait. X-rays show medial beaking of the proximal tibia and an increased metaphyseal-diaphyseal angle. What is the most likely diagnosis? A) Physiologic genu varum B) Rickets C) Blount’s disease D) Skeletal dysplasia

Answer 53

C) Blount’s disease 📝 Rationale: Nelson’s describes Blount’s disease (tibia vara) as a progressive pathologic condition caused by abnormal medial growth plate compression. Seen in obese children and early walkers. X-ray findings: Medial beaking, metaphyseal-diaphyseal angle > 11°. Tx: Bracing in mild cases (<3 years), surgery if severe or progressive.

Question 54

2. A 5-year-old boy with a history of premature birth presents with difficulty walking. His gait is stiff, and his legs cross over each other when walking. On exam, he has increased tone in his hip adductors, hyperreflexia, and equinovarus foot deformity. What is the most likely diagnosis? A) Duchenne muscular dystrophy B) Cerebral palsy (CP) C) Charcot-Marie-Tooth disease D) Spinal muscular atrophy

Answer 54

B) Cerebral palsy (CP) 📝 Rationale: Nelson’s highlights the "scissoring gait" as characteristic of spastic cerebral palsy. Hypertonia and hyperreflexia confirm an upper motor neuron disorder. Equinovarus foot deformity is common due to ankle contractures. Tx: Physical therapy, botulinum toxin, and surgical release for severe contractures.

Question 55

3. A 4-year-old boy is being evaluated for delayed motor milestones. He has difficulty rising from the floor, requiring the use of his hands to "climb up his legs." His calves appear enlarged. Genetic testing confirms an X-linked disorder. What is the most likely diagnosis? A) Spinal muscular atrophy B) Becker muscular dystrophy C) Duchenne muscular dystrophy D) Myotonic dystrophy

Answer 55

C) Duchenne muscular dystrophy 📝 Rationale: Nelson’s emphasizes that Duchenne muscular dystrophy (DMD) presents with progressive weakness and the Gower’s sign (using hands to climb up the legs when standing). Calf pseudohypertrophy is due to fatty replacement of muscle. Genetics: X-linked recessive mutation in the dystrophin gene. Tx: Glucocorticoids, PT, respiratory support, cardiac monitoring.

Question 56

4. A 10-year-old boy with Becker muscular dystrophy is evaluated for new onset of fatigue and exertional dyspnea. He has mild proximal muscle weakness and no wheelchair dependence. Which of the following complications is most concerning at this stage? A) Progressive scoliosis B) Dilated cardiomyopathy C) Respiratory insufficiency D) Gastrointestinal dysmotility

Answer 56

B) Dilated cardiomyopathy 📝 Rationale: Nelson’s highlights that Becker muscular dystrophy (BMD) progresses slower than DMD but has a high risk of developing dilated cardiomyopathy. Cardiac disease can occur before significant skeletal muscle weakness. Tx: Early initiation of ACE inhibitors and beta-blockers can help delay progression.

Question 57

5. A 7-year-old boy with cerebral palsy presents with worsening lower extremity spasticity and equinovarus foot deformity. He has increasing difficulty walking despite prior therapy. What is the most appropriate next step? A) Physical therapy and continued observation B) Botulinum toxin injections C) Orthopedic surgery for tendon lengthening D) Corticosteroids

Answer 57

B) Botulinum toxin injections 📝 Rationale: Nelson’s recommends botulinum toxin injections for managing spasticity in CP before considering surgery. Targets muscle overactivity and prevents fixed contractures. Surgical tendon release is only indicated in severe, persistent cases.